Hi Madrus.
Plant-based sources of 5-meO is a fascinating field and as you indicated, perhaps not one of the more-prevalent 5-MeO products in the global scheme of this medicine's consumption, although in remote areas where species like Virola and Anadenanthera are prevalent and have a traditional history of use, such sources may be more common.
I do however have some optimism that new sources may come to light as intrepid ethnobotanists and amateur explorers seek out alternative natural (and perhaps sustainable) sources.
cheers,